| 摘要 |
a -Methyl-g -butyrolactone is prepared by hydroformylating a methacrylic ester with carbon monoxide and hydrogen in the presence of a rhodium-containing catalyst at temperatures between 125 DEG and 200 DEG , preferably 140 DEG and 180 DEG C. and at gas pressures between 75 and 1000 atmospheres and subsequently hydrogenating the resulting product (a b -formylisobutyric acid ester). The methacrylic ester is preferably an ester of an alkanol of 3 atoms or less. The rhodium - containing catalyst, preferably rhodium sesquioxide may be used in amounts between 0.0004 to 0.004 gram atoms mole of ester, and in quantities of 1 to 40% by weight based on the weight of carrier, if present. The hydroformylation is preferably also carried out in the presence of 0.01 to 10% by weight of a tertiary amine. The molar ratio of carbon monoxide to hydrogen is preferably between 2:1 and 1:4 and the combined pressure is in the range 150 to 500 atmospheres. The hydroformylation product may be hydrogenated without removing rhodium carbonyl compounds by raising the temperature above 200 DEG C., and keeping the pressure over 150 atmospheres. In any case, the temperature should be raised above 180 DEG C. during or after hydrogenation. |
